This invention relates to a large flexible container for gaseous, liquid, or pourable products with a tear-resistant outer shell and with a replaceable inner liner.
Large containers of this type are known from DE-PS 33 36 077. Besides the problems of undesirable air inclusions between the outer shell and the inner liner described in this German Patent, such large flexible containers can be handled only with difficulty when being set up and filled. The inner liner has to be introduced into the outer shell through the manhole, and to do this a man has to crawl into the outer shell to mount the fittings necessary for filling, emptying, and venting the inner liner. In this procedure, it is not impossible for dirt also to be introduced into the outer shell, which can destroy the relatively thin and sensitive inner liner even when being filled.
It is the purpose of this invention to propose a new design for such large flexible containers and a new procedure by which such containers can be set up and filled considerably more easily and with fewer problems.
According to the instructions of the invention, a large flexible container of this type is designed with a so-called front face from which the large container extends in an essentially elongated form. The cross-sectional shape of the large container is intended to be designed so that it conforms to the natural spreading forces of a drop of water standing on the bottom, to guarantee that no peak stresses can build up in the outer shell from the pressure of filling. This applies also to the front face, which has a bulged design corresponding to the filling pressure decreasing from bottom to top.
The front face thus provided is reinforced pursuant to the invention by at least one flexibly pliable bar that extends essentially perpendicular to the base over the front face when the container is filled. This reinforcement of the front face is necessary when the container is still untilled in order to be able to erect the front face of the outer shell ahead of time, i.e., to bring the front face into an almost vertical position after initially laying out the outer shell flat on the floor at the particular location, so that an operator can approach the front face without stepping on it. The pliable properties of such a reinforcing bar at the same time make it possible for the front face to bulge out later corresponding to the filling pressure when the container is being filled.
The erection of the front face requires a large container such that there is at least one point of attack for pulling at the top of the front face in the form of an eye or the like. The front face can then be erected relatively easily by means of a pull cord, especially when the pull cord is suitably pulled over a roller at a higher level (for example, on a tripod, a ladder, or the like). According to the instructions of the invention, both the manhole sealed linearly, preferably with a linear closure aligned essentially perpendicular to the bottom or to the base of the container, and all fittings necessary for filling, emptying, and venting the inner tank are also located on the front face.
This provides the advantage of the front operation pursuant to the invention. The inner liner can be inserted into the outer shell through the manhole in the front face, without having to enter the outer shell for the purpose, and at the same time, all of the necessary fittings that have to be connected to the inner liner and fed through the outer shell can also be assembled through the manhole in the front face, specifically without entering the outer shell, since according to the instructions of the invention all of the necessary fittings of the inner liner are positioned on the front face of the container, readily accessible after erection.
It is also very advantageous according to the instructions of the invention to provide a compressed air connector in the front shell that is readily accessible in the new large container for inflating only the outer shell.
A large container pursuant to the invention with the aforementioned basic features, suitable refinements of which will be described later, can be set up and filled especially easily and with no problems within the context of the problem posed by the invention, using the following operating procedure.
The new operating procedure is characterized by the fact that after laying out the outer shell flat on the floor at the particular location, the front face reinforced by at least one flexibly pliable bar is set up using the pulling force point of attack present at the top of the front face, whereupon the inner liner packed in the form of a roll is laid in the outer shell through the manhole on the front and without entering the outer shell, with the roll axis perpendicular to the lengthwise direction of the outer shell, and the fittings likewise to be mounted on the front face through the manhole are again connected without entering the outer shell, and by the fact that after sealing the manhole, only the outer shell is then largely inflated at first to stretch it out free of folds on the floor of the location, if necessary with the outer shell vent restricted or closed, and by the fact that the outer shell is then vented again somewhat so that it drops down somewhat in height and thereby stands flat on the floor with its base spread out, whereupon the inner liner still present in roll form is completely unrolled on the spread surface of the outer shell by introducing compressed air into the inner liner, and the inner liner is then filled with simultaneous venting of the outer shell.
A suitable design of the invention provides that the upper vent opening for the outer shell is located at the top of the front face, and that this vent opening has the form of an outer shell vent that can be sealed and/or restricted.
By means of such an outer shell vent at the top of the front face, the exhaust air can be controlled with no problems both when inflating only the outer shell and also during the subsequent venting of the outer shell to lower the height and spread out the base.
It is proposed for cost reasons that the outer shell vent at the top of the front face also serve at the same time in a structural unit as the compressed air connector for inflating only the outer shell.
It is also suggested as being very advantageous to provide the outer shell with tear-off vents or tear-off flaps, preferably in the lower corner areas of the large container, to vent the space between the outer shell and the inner liner, which can be operated from the front face of the large container by means of a pull cord or the like.
Such tear-off vents or tear-off flaps solve the venting problem of the air that may be enclosed between the outer shell and the inner liner while filling the container, very much more easily and more effectively than the combshaped spacing elements described for venting purposes in the mentioned DE-PS 33 36 077. Furthermore, such tear-off vents or tear-off flaps have the advantage that they stay closed at first, which is definitely helpful in the operating procedure according to the instructions of the invention for the initial inflation of only the outer shell, and are torn away, i.e. opened, only when it is necessary to vent between the outer shell and the inner liner when filling the container. Such tear-away vents or tear-away flaps can be particularly simple devices consisting of Velcro tape fasteners or a bar closure as shown in the drawing.
Another suitable embodiment of the invention provides for the linear closure of the manhole to extend essentially perpendicular to the base over the front face, and for the linear closure to consist of at least one flexibly pliable flat bar that can be pushed into loops in the manhole closure.
This flat bar or optionally two flat bars that constitute the manhole closure can at the same time perform the function of reinforcing the front face, so that in this case no separate additional bar is necessary just for reinforcing the front face.
It is especially suitable to extend the bar linear closure of the manhole up to the top area of the front face, and then to place at least the fittings for filling and venting the inner liner above the linear closure at the top of the front face. This permits the fittings for the inner liner to be mounted quickly and securely through the manhole by simply reaching through by hand.
Naturally, it is also again very economical with regard to the fittings for the inner liner to combine all of the fittings necessary for filling, emptying, and venting the inner liner into one structural unit, and to position this at the top of the front face. The container is then emptied from the top by means of a suction tube that is inserted into the inner liner through the fitting, and it is possible to fill and ventilate the inner liner with no problems anyhow through the structural unit located at the top.
The reinforcement of the front face of the flexible outer shell and its subsequent erection provided for by the instructions of the invention are facilitated in a suitable form of embodiment of the invention by the fact that the front face has two other flexibly pliable bars on the outside from the central manhole closure to reinforce the front face, which can be inserted into pocket loops on the front face of the outer shell, with the bars also being usable through cutouts between the pocket loops as a point of attack for pulling and/or as a handle.